Piezoelectric Discharge Driver Layout for High-Low Voltage Noise Isolation
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Solution Overview
Problem
Existing liquid discharge apparatuses face challenges in reducing noise interference from high-voltage circuits on low-voltage circuits, affecting discharge accuracy in ink jet printers due to the integration of high-voltage and low-voltage circuits within the same IC chip.
Innovation Solution
A liquid discharge apparatus with a circuit substrate design that separates high-voltage and low-voltage circuits by optimizing the placement of power source terminals and input terminals, reducing noise influence through strategic placement and integration of gate drivers and control circuits within the IC device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If high-voltage and low-voltage circuits are integrated in the same IC chip, then device complexity is reduced, but noise interference from high-voltage circuits affects low-voltage circuits
Solution Approach 1:
The IC chip is segmented into distinct high-voltage circuit regions and low-voltage circuit regions, with each region independently laid out on the substrate. This spatial segmentation allows both voltage levels to coexist on the same chip while minimizing mutual interference, resolving the contradiction between integration and noise isolation.
Solution Approach 2:
Different regions of the IC chip are assigned different electrical characteristics - high-voltage regions use appropriate voltage levels and shielding, while low-voltage regions use noise-resistant design techniques. This local differentiation allows each region to be optimized for its specific function while maintaining overall integration.
2Measurement precision
If class D amplifiers are used for high-frequency operation (1 to 8 MHz), then discharge accuracy is improved, but electromagnetic interference is likely to be generated
Solution Approach 1:
The high-frequency class D amplifier circuit that generates EMI is extracted and separated from the low-voltage control circuits on the IC chip. By physically separating these circuits spatially, the harmful EMI is isolated from sensitive low-voltage operations, allowing high discharge accuracy to be maintained without excessive interference to control functions.
3Loss of energy
If division power source type driving circuit is used, then energy efficiency is improved and EMI is suppressed, but high-voltage and low-voltage circuits must coexist in the same IC chip
Solution Approach 1:
The division power source type driving circuit is implemented with segmented layout, separating high-voltage switching transistors from low-voltage control logic on the IC chip. This spatial segmentation maintains the energy efficiency benefits of the division power source architecture while isolating noise from the high-voltage section, preventing interference with low-voltage operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces noise interference, improving the accuracy of the driving signal and enhancing discharge precision by isolating high-voltage and low-voltage circuit noise, thereby improving ink discharge accuracy.
Implementation Method 1
A piezoelectric element is provided corresponding to each of a plurality of nozzles in the head unit, each of the piezoelectric elements is driven according to a driving signal, and accordingly, a predetermined amount of ink (liquid) is discharged from the nozzle
Data Source
AI summary
There is provided a liquid discharge apparatus including: a discharge unit which discharges a liquid by a piezoelectric element; and a driving circuit which drives the piezoelectric element, in which the driving circuit includes a first transistor pair which is driven by a first power source voltage and a second power source voltage, a second transistor pair which is driven by the second power source voltage and a third power source voltage, and a first control circuit which controls on a first input signal, and in which, the shortest distance between the first power source voltage and the first input terminal is shorter than the shortest distance between the second power source voltage and the first input terminal, and the shortest distance between the second power source terminal and the first input terminal is shorter than the shortest distance between the third power source voltage and the first input terminal.